A new method for the calibration of strain cylinders using laser interferometry

Abstract

This research investigates the possibility of calibrating strain cylinders using laser interferometry, thus providing a new type of transducer that can provide both force and deformation indications. This new method for the calibration of strain cylinders is based on the application of a dual channel laser interferometer in a force standard machine. Using the proposed new method, the relationship between force, deformation, and strain can be calibrated in parallel when calibration forces are applied according to the procedure outlined in ISO 376. Experimental results show that the deformation of a strain cylinder has a definite and stable relationship with the force applied and can be calibrated and directly traced to the wavelength of the laser. Therefore, a new standard that can be used for both alignment verification and indication verification of compression testing machines and other uniaxial testing machines is proven. The research also illustrates the possibility of providing a new deformation-type force transducer using a non-gauged steel cylinder together with a multi-channel laser interferometer.